Bert told me to use fine graphite to lubricate the shutter on my 135mm lens. That did it. Roughly one hundred firings for each speed took care of the problems._________________Nothing beats a good piece of glass.

Excess friction is only one of several possible causes of slow running of a shutter. Cleaning and PROPER lubrication corrects only this cause of slow speeds. Another possible cause is the loss of strength of the spring(s) in the mechanism which will not be corrected by cleaning and proper lubrication.
Frequently, slow running is caused by a combination of causes and no one fix cures the problem by itself!